Cardiovascular disease and ischemic heart disease is the #1 killer in Canada. Currently, Cardiac invasive catheterization angiography (CICA) is the gold standard for the assessment of the arteries in the heart. However, cardiac catheterization has risks which prohibit its use in all patients. These risks include: death, heart attack, stroke and bleeding. Cardiac computed tomography angiography (CTA) is a new non-invasive technology which may enable the evaluation of patients' coronary anatomy without exposing patients to the risks of invasive cardiac catheterization.